Dynamic control of uplink communication from a dual-connected device, based on antenna pattern efficiency per connection

ABSTRACT

A method and system for controlling uplink communication from a user equipment device (UE) that has at least two co-existing air-interface connections including a first air-interface connection with a first access node and a second air-interface connection with a second access node. An example method includes comparing a level of antenna pattern efficiency associated with the first air-interface connection with a level of antenna pattern efficiency associated with the second air-interface connection and, based at least on the comparing, configuring an uplink split ratio defining a distribution of uplink user-plane data flow of the UE between at least the first air-interface connection and the second air-interface connection. In an example implementation, this could involve configuring one of the air-interface connections as a primary uplink path to which the UE restricts its uplink communication unless and until a trigger occurs for transitioning the UE to operate in an split-uplink mode.

BACKGROUND

A typical wireless communication system includes a number of accessnodes that are configured to provide coverage in which user equipmentdevices (UEs) such as cell phones, tablet computers,machine-type-communication devices, tracking devices, embedded wirelessmodules, and/or other wirelessly equipped communication devices (whetheror not user operated), can operate. Further, each access node could becoupled with a core network that provides connectivity with variousapplication servers and/or transport networks, such as the publicswitched telephone network (PSTN) and/or the Internet for instance. Withthis arrangement, a UE within coverage of the system could engage inair-interface communication with an access node and could therebycommunicate via the access node with various application servers andother entities.

Such a system could operate in accordance with a particular radio accesstechnology (RAT), with communications from an access node to UEsdefining a downlink or forward link and communications from the UEs tothe access node defining an uplink or reverse link.

Over the years, the industry has developed various generations of RATs,in a continuous effort to increase available data rate and quality ofservice for end users. These generations have ranged from “1G,” whichused simple analog frequency modulation to facilitate basic voice-callservice, to “4G”—such as Long Term Evolution (LTE), which nowfacilitates mobile broadband service using technologies such asorthogonal frequency division multiplexing (OFDM) and multiple inputmultiple output (MIMO). And recently, the industry has completed initialspecifications for “5G” and particularly “5G NR” (5G New Radio), whichmay use a scalable OFDM air interface, advanced channel coding, massiveMIMO, beamforming, and/or other features, to support higher data ratesand countless applications, such as mission-critical services, enhancedmobile broadband, and massive Internet of Things (IoT).

In accordance with the RAT, each access node could be configured toprovide coverage and service on one or more radio-frequency (RF)carriers. Each such carrier could be frequency division duplex (FDD),with separate frequency channels for downlink and uplink communication,or time division duplex (TDD), with a single frequency channelmultiplexed over time between downlink and uplink use. And each suchfrequency channel could be defined as a specific range of frequency(e.g., in RF spectrum) having a bandwidth and a center frequency andthus extending from a low-end frequency to a high-end frequency.

Further each carrier could be defined within an industry standardfrequency band, by its frequency channel(s) being defined within thefrequency band. Examples of such frequency bands include (i) bands 2, 4,12, 25, 26, 66, 71, and 85, supporting FDD carriers (ii) band 41,supporting TDD carriers, and (iii) bands n258, n260, and n261,supporting FDD and TDD carriers, among numerous other possibilities.

On the downlink and uplink, the air interface provided by an access nodeon a given carrier could be configured in a specific manner to definephysical resources for carrying information wirelessly between theaccess node and UEs.

Without limitation, for instance, the air interface could be dividedover time into a continuum of frames, subframes, and symbol timesegments, and over frequency into subcarriers that could be modulated tocarry data. The example air interface could thus define an array oftime-frequency resource elements each being at a respective symbol timesegment and subcarrier, and the subcarrier of each resource elementcould be modulated to carry data. Further, in each subframe or othertransmission time interval, the resource elements on the downlink anduplink could be grouped to define physical resource blocks (PRBs) thatthe access node could allocate as needed to carry data between theaccess node and served UEs.

In addition, certain resource elements on the example air interfacecould be reserved for special purposes. For instance, on the downlink,certain resource elements could be reserved to carry reference signalsor the like that UEs could measure in order to determine coveragestrength, and other resource elements could be reserved to carry othercontrol signaling such as PRB-scheduling directives and acknowledgementmessaging from the access node to UEs. And on the uplink, certainresource elements could be reserved to carry random access signalingfrom UEs to the access node, and other resource elements could bereserved to carry other control signaling such as PRB-schedulingrequests, acknowledgement messaging, and channel-quality reports fromUEs to the access node.

To facilitate providing this coverage and service, each access nodecould be configured with one or more antennas, power amplifiers andassociated circuitry, cooperatively enabling the access node to transmitand receive electromagnetic signals in a region defined by an antennapattern.

The antenna pattern of an access node could define a coverage footprintin which the access node can engage in downlink transmission to UEs andreceive uplink transmission from UEs. Such an antenna pattern could havea main lobe and could be characterized by an azimuth angle, an elevationangle, a beamwidth, and a radius. In polar coordinates, the azimuthangle could define a direction of radiation of the main lobe within ahorizontal plane, as an angle of rotation around a vertical axis (inrelation to North (zero degrees) for instance), the elevation anglecould define a direction of radiation of the main lobe within a verticalplane, as an angle of rotation around a horizontal axis (in relation tothe horizon for instance), and the beamwidth could define an angularwidth of the main lobe within the horizontal plane, typically measuredbetween half-power (−3 dB) points of the main lobe for instance.Further, the radius of the antenna pattern could define the effectivedistance of radiation from the access node as measured at a ground planefor instance, among other possibilities.

OVERVIEW

When a UE enters into coverage of an example network, the UE coulddetect threshold strong coverage of an access node on a particularcarrier (e.g., a threshold strong reference signal broadcast by theaccess node on the carrier) and could then engage in random-access andconnection signaling, such as Radio Resource Control (RRC) signaling, toestablish an air-interface connection (e.g., RRC connection) throughwhich the access node will then serve the UE on that carrier.

Further, if the UE is not already registered for service with the corenetwork, the UE could transmit to the access node an attach request,which the access node could forward to a core-network controller forprocessing. And the core-network controller and access node could thencoordinate setup for the UE of one or more user-plane bearers, eachincluding (i) an access-bearer portion that extends between the accessnode and a core-network gateway system that provides connectivity with atransport network and (i) a data-radio-bearer portion that extends overthe air between the access node and the UE.

Once the UE is so connected and registered, the access node could thenserve the UE in a connected mode over the air-interface connection,managing downlink air-interface communication of packet data to the UEand uplink air-interface communication of packet data from the UE.

For instance, when the core-network gateway receives user-plane data fortransmission to the UE, the data could flow to the access node, and theaccess node could buffer the data, pending transmission of the data tothe UE. With the example air-interface configuration noted above, theaccess node could then allocate downlink PRBs in an upcoming subframefor carrying at least a portion of the data, defining a transport block,to the UE. And the access node could then transmit to the UE in acontrol region of that subframe a Downlink Control Information (DCI)scheduling directive that designates the allocated PRBs, and the accessnode could accordingly transmit the transport block to the UE in thosedesignated PRBs.

Likewise, on the uplink, when the UE has user-plane data fortransmission on the transport network, the UE could buffer the data,pending transmission of the data to the access node, and the UE couldtransmit to the access node a scheduling request that carries a bufferstatus report (BSR) indicating the quantity of data that the UE hasbuffered for transmission. With the example air-interface configurationnoted above, the access node could then allocate uplink PRBs in anupcoming subframe to carry a transport block of the data from the UE andcould transmit to the UE a DCI scheduling directive that designatesthose upcoming PRBs. And the UE could then accordingly transmit thetransport block to the access node in the designated PRBs.

For each such scheduled downlink or uplink communication on PRBs betweenan access node and a UE, the access node and UE could use a modulationand coding scheme (MCS) that the access node selects based on the UE'swireless channel quality and the access node specifies in its schedulingdirective to the UE.

In a representative implementation, the MCS could define a coding ratebased on the extent of error-correction coding data or the like thatwould be transmitted together with the user-plane data beingcommunicated, and a modulation scheme that establishes how many bits ofdata could be carried by each resource element. When channel quality isbetter, the access node may direct use of a higher-order MCS that has ahigher coding rate (e.g., with more error-correction coding) and/or hatsupports more bits per resource element, and when channel quality isworse, the access node may direct use of a lower-order MCS that may havea lower coding rate and/or supports fewer bits per resource element.

Examples of modulation schemes include, without limitation, quadraturephase-shift keying (QPSK), in which each resource element represents 2bits of data, 8 phase-shift keying (8PSK), in which each resourceelement represents 3 bits of data, 16 quadrature amplitude modulation(16QAM), in which each resource element represents 4 bits of data,32QAM, in which each resource element represents 5 bits of data, 64QAM,in which each resource element represents 6 bits of data, and 256QAM, inwhich each resource element represents 8 bits of data.

The access node could determine the MCS to be used use in a giveninstance primarily based on wireless channel quality reported by the UE.For example, as the access node serves the UE, the UE could transmitchannel quality reports to the access node periodically and/or as partof the UE's scheduling requests or other communications to the accessnode, with each report including a channel-quality indicator (CQI) valuerepresenting the UE's determined channel quality and perhaps one or moreother channel metrics such as downlink reference signal receive power(RSRP), signal-to-interference-plus-noise ratio (SINR), or the like.When the access node schedules communications to or from the UE, theaccess node could then map the UE's latest reported CQI value to acorresponding MCS value using a standard CQI-MCS mapping table, and theaccess node could direct use of that MCS in the scheduling directivethat the access node sends to the UE. Communication could thus occurusing that directed MCS.

Further, for uplink communication from a UE, the access node couldadditionally base its selection of MCS on a consideration of the UE'spower headroom, namely, the extent to which the UE is able to transmitat a power level that is high enough to provide the access node withsufficient uplink SINR.

In practice, as the access node serves the UE, the access node couldregularly estimate SINR of transmissions that the access node receivesfrom the UE and could compare the SINR with an SINR set point (e.g.,dynamically established based on observed error rate) and accordinglydirect the UE to either increment or decrement the UE's transmit power.And on an ongoing basis, the UE could compute its power headroom as thedifference between a configured maximum transmit power level (e.g.,maximum average transmit power) of the UE and the power level at whichthe UE should be transmitting based on the power-control commands fromthe access node.

Each time the UE sends a scheduling request to the access node, the UEcould include in the scheduling request a power-headroom report (PHR)indicating the UE's current power headroom. (Such a report mayeffectively indicate the UE's power headroom by providing a value thatmaps to, equals, or otherwise represents the UE's power headroom.) Andthe access node could then use that reported power headroom as a basisto set or adjust the MCS that the access node will direct the UE to usefor uplink transmission. If the power headroom is negative, forinstance, the access node might artificially reduce the MCS-order fromthe MCS that corresponds with the UE's reported CQI.

When the industry advances from one generation of wireless technology tothe next, or in other scenarios, networks and UEs may also supportdual-connectivity service, where a UE is served on co-existingconnections, perhaps according to multiple different RATs.

For instance, a first access node could be configured to provide serviceaccording to a first RAT and a second access node could be configured toprovide service according to a second RAT, and a UE positionedconcurrently within coverage of both the first and second access nodescould have a first radio configured to engage in service according tothe first RAT and a second radio configured to engage in serviceaccording to the second RAT. With this arrangement, the UE may be ableto establish a first air-interface connection with the first access nodeaccording to the first RAT and a second air-interface connection withthe second access node according to the second RAT, and the access nodesmay then concurrently serve the UE over those connections according totheir respective RATs.

Such dual connectivity (or “non-standalone” connectivity) could helpfacilitate increased peak data-rate of communications, by multiplexingthe UE's communications across the multiple air-interface connections.Further or alternatively, dual connectivity may provide other benefitscompared with serving a UE on a single connection (as “standalone”connectivity).

In a representative dual-connectivity implementation, one of the accessnodes could operate as a master node (MN), responsible for coordinatingsetup, management, and teardown of dual-connectivity service for the UEand functioning as an anchor point for RRC signaling and core-networkcontrol signaling related to the dual-connected UE. And each of one ormore other access nodes could operate as a secondary node (SN) mainly toprovide additional connectivity and increased aggregate bandwidth forthe UE.

In such an implementation, the UE might initially establish a firstair-interface connection between the UE and the MN in the manner notedabove for instance. And upon determining that the UE supportsdual-connectivity service, the MN might then coordinate setup of dualconnectivity for the UE.

Coordinating setup of dual connectivity for the UE could involveengaging in signaling to coordinate setup of a second air-interfaceconnection between the UE and the SN. For instance, the MN could engagein signaling with the SN to arrange for setup of the second connection,and the MN could engage in signaling with the UE to cause the UE toaccess the SN and complete setup of the second connection.

In addition, coordinating setup of dual connectivity for the UE couldalso involve engaging in signaling, for each of one or more bearersestablished for the UE, to split the bearer so that the MN and SN canthen each serve a portion of the UE's data communications. For instance,the MN could engage in signaling to establish a bearer split at thecore-network gateway system, with one access-bearer leg extendingbetween the gateway system and the MN and another access-bearer legextending between the gateway system and the SN. Alternatively, the MNcould engaging signaling to establish a bearer split at the MN, with theUE's access bearer remaining anchored at the MN and a branch of theaccess bearer extending between the MN and the SN. And stillalternatively, the MN could engage in signaling to establish a bearersplit at the SN, with the UE's access bearer being transferred to andanchored at the SN and a branch of the access bearer extending betweenthe SN and the MN.

With dual-connectivity so configured by way of example, the MN and SNcould then serve the UE with packet-data communications over theirrespective connections with the UE, with each access node coordinatingair-interface communication in the manner described above for instance.

In an example implementation, the UE's downlink user-plane data flowwould be split between the UE's two connections. For instance, when thecore-network gateway system has data destined to the UE, that data couldflow over a split bearer like one of those noted above, with the MNultimately receiving a portion of the data and transmitting that portionof data over the UE's first air-interface connection to the UE, and withthe SN ultimately receiving another portion of the data and transmittingthat other portion of data over the UE's second air-interface connectionto the UE. Further, if the MN is the controller of the UE'sdual-connectivity service, the MN could be responsible for configuring adownlink split ratio such as what percentage of the UE's downlink dataflow would be so handled by the MN versus by the SN.

Likewise, the UE's uplink user-plane data flow could also be splitbetween the UE's two connections. For instance, when the UE has data totransmit on the transport network, the UE could transmit a portion ofthat data over its first air-interface connection to the MN, and thatdata could flow over an access bearer from the MN to the core-networkgateway system for output onto the transport network, and the UE couldtransmit another portion of the data over its second air-interfaceconnection to the SN, and that data could similarly flow over an accessbearer from the SN to the core-network gateway system for output ontothe transport network. And similarly here, if the MN is the controllerof the UE's dual-connectivity service, the MN could be responsible forconfiguring an uplink split ratio such as what percentage of the UE'suplink data flow the UE should transmit over its first air-interfaceconnection to the MN versus over its second air-interface connection tothe SN.

As to the uplink data split in dual connectivity, one of the UE'sconnections could also be designated as the UE's “primary uplink path,”and the UE's other connection could be designated as the UE's “secondaryuplink path.” For instance, the UE's air-interface connection with theMN could be designated as the UE's primary uplink path, and the UE'sair-interface connection with the SN could be designated as the UE'ssecondary uplink path. Or the UE's air-interface connection with the SNcould be designated as the UE's primary uplink path, and the UE'sair-interface connection with the MN could be designated as the UE'ssecondary uplink path.

In an example implementation, the UE could be configured by default tooperate in a single-connection-uplink mode in which the UE would limitits uplink data flow to just its primary uplink path. And uponoccurrence of a trigger, such as threshold high uplink data flow fromthe UE, the UE may then transition from the single-connection-uplinkmode to a split-uplink mode in which the UE will split its uplink dataflow between its primary and secondary uplink paths.

In this implementation as well, if the MN is the controller of the UE'sdual-connectivity, the MN could be responsible for designating which ofthe UE's connections will be the UE's primary uplink path. Further, asnoted above, when the UE will operate in the uplink-split mode, the MNcould be responsible for configuring the UE's uplink split ratio.

One technical concern that could arise in such a system is that, whenmultiple access nodes concurrently serve a UE each over a respectiveair-interface connection in a respective coverage area, the access nodesmay each have a respective level of antenna pattern efficiency thatcould impact quality of their air-interface communications with the UE.

An access node's antenna pattern efficiency as to the coverage area inwhich the access node serves the UE could be a physical attributerepresenting how well the access node's antenna structure focuses energyin a desired area or direction of that coverage area rather than in anundesired area or direction. Without limitation, exampleantenna-pattern-efficiency metrics could include (i) inverse sectorpower ratio (SPR), as a ratio of the power of the antenna pattern's mainlobe that the antenna structure radiates in the desired area to thepower of the antenna pattern's main lobe that the antenna structureradiates outside of that desired area, and (ii) front to back ratio(FBR), as a ratio of the power of the antenna structure's radiation in amain lobe of the antenna pattern to the power of the antenna structure'sradiation in a back lobe of the antenna pattern, as well as combinationsof these or other metrics.

The antenna pattern efficiency of the antenna structure that an accessnode uses to provide the coverage area in which the access node serves aUE could impact the quality of air-interface communication between theUE and the access node in that coverage area. For instance, higherantenna pattern efficiency could facilitate improved quality ofair-interface communication between the access node and the UE, such asby allowing increased channel receive power, increased SINR, andincreased power headroom, any or all of which might correlate withhigher peak throughput.

Therefore, the present disclosure provides for taking into account thelevels of antenna pattern efficiency corresponding respectively witheach of a dual-connected UE's air-interface connections, and using thoselevels of antenna pattern efficiency as a basis to control the UE'suplink air-interface communication. In one respect, for instance, basedon a comparison of the levels of antenna pattern efficiencycorresponding with the UE's multiple air-interface connections, the UE'sserving MN could configure as the UE's primary uplink path theair-interface connection that has the highest level of antenna patternefficiency. And in another respect, based on such a comparison, the MNcould configure an uplink split ratio for the UE, such as by setting theuplink split ratio to be provide a majority of the UE's uplink data flowon the air-interface connection that has the highest level of antennapattern efficiency.

These as well as other aspects, advantages, and alternatives will becomeapparent to those of ordinary skill in the art by reading the followingdetailed description, with reference where appropriate to theaccompanying drawings. Further, it should be understood that thedescriptions provided in this overview and below are intended toillustrate the invention by way of example only and not by way oflimitation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an example wirelesscommunication system in which features of the present disclosure can beimplemented.

FIG. 2 is a polar plot illustrating an example antenna pattern withexample desired and undesired areas of radiation.

FIG. 3 is a polar plot illustrating an example antenna pattern withexample front and back lobes.

FIG. 4 is a flow chart depicting an example method in accordance withthe disclosure.

FIG. 5 is another flow chart depicting an example method in accordancewith the disclosure.

FIG. 6 is a simplified block diagram of an example access node operablein accordance with the disclosure.

DETAILED DESCRIPTION

An example implementation will now be described in the context of 4GLTE, 5G NR, and 4G-5G dual connectivity, referred to as EUTRA-NR DualConnectivity (EN-DC).

With EN-DC, a 4G access node (4G evolved Node-B (eNB)) functions as theMN, and a 5G access node (5G next-generation Node-B (gNB)) functions theSN. Thus, a UE would first establish a standalone-4G connection with a4G eNB, and the 4G eNB could then coordinate setup of EN-DC service forthe UE, including setup for the UE of a secondary 5G connection with the5G gNB. And the 4G eNB and 5G gNB could then concurrently serve the UEover their respective 4G and 5G connections with the UE.

It should be understood, however, that the principles disclosed hereincould extend to apply with respect to other scenarios as well, such aswith respect to other RATs and other dual-connectivity configurations.Further, it should be understood that other variations from the specificarrangements and processes described are possible. For instance, variousdescribed entities, connections, functions, and other elements could beadded, omitted, distributed, re-located, re-ordered, combined, orchanged in other ways. In addition, it will be understood that technicaloperations disclosed as being carried out by one or more entities couldbe carried out at least in part by a processing unit programmed to carryout the operations or to cause one or more other entities to carry outthe operations

Referring to the drawings, as noted above, FIG. 1 is a simplified blockdiagram of an example wireless communication system in which variousdisclosed features could be implemented. In particular, the examplesystem includes a cell site 12 having a 4G eNB 14 and a 5G gNB 16, eachbeing coupled with an example core network 18.

Access nodes 14, 16 could be macro access nodes of the type configuredto provide a wide range of coverage or could take other forms, such assmall cell access nodes, relays, femtocell access nodes, or the like,possibly configured to provide a smaller range of coverage.

In addition, each access node could be configured to provide coverageand service on one or more carriers, each carrier being in a givenfrequency band and having a given duplex mode (e.g., FDD or TDD). In theexample shown, for instance, the 4G eNB 14 is configured to providecoverage and service on at least one carrier 20, which might be definedin given frequency band. And the 5G gNB 16 is configured to providecoverage and service on at least one carrier 22, which might be in thesame or another frequency band.

The air interface on each carrier could be structured as described aboveby way of example, being divided over time into frames, subframes, andsymbol time segments, and over frequency into subcarriers, thus definingan array of air-interface resource elements grouped into PRBs allocableby the access node as noted above, for use to carry data to or fromserved UEs. Carrier-structure and/or service on the 4G and 5Gair-interfaces, however, could differ from each other in various waysnow known or later developed, such as with one implementing variablesubcarrier spacing and the other having fixed subcarrier spacing, withone having flexible TDD configuration and the other having fixed TDDconfiguration, with one having different subcarrier spacing and/orsymbol time segment length than the other, and/or with one makingdifferent use of MIMO technologies than the other, among otherpossibilities.

In an example implementation as shown in FIG. 1, each of the accessnodes 14, 16 could include at least one antenna structure, which theaccess node could use to provide a coverage area on its illustratedcarrier. In particular, the 4G eNB 14 is shown including an antennastructure 24 that radiates to provide a coverage area on carrier 20, andthe 5G gNB 16 is shown including an antenna structure 26 that radiatesto provide a coverage area on carrier 22.

Without limitation, each access node's antenna structure might includean antenna array, having on the order of 2 to 8 antennas or perhaps amassive-MIMO antenna array having many more antennas, perhaps on theorder of tens, hundreds, or even thousands of antennas. Alternatively,the access nodes might share use of a common antenna array, perhaps acommon massive-MIMO array, with the 4G eNB 14 being configured to use asubset of the antennas and the 5G gNB 16 being configured to use anothersubset of the antennas. Other arrangements are possible as well.

Each access node's antenna structure could be configured to provide itscoverage area with an antenna pattern as noted above, having a main lobeor major lobe and being characterized by an azimuth angle, an elevationangle, a beamwidth, and a radius. As noted above, the beamwidth of theantenna pattern could define an angular width of its main lobe within ahorizontal plane, typically measured between half-power (−3 dB) pointsof the main lobe for instance. Without limitation, the beamwidth of eachaccess node's antenna pattern might be on the order of 65 to 120degrees. In particular, an access node's antenna structure may bedesigned or configured to radiate with that width of coverage, whichcould define a desired width of a representative cell sector.

Due to imperfections in antenna design and configurations, and given thetypical definition of beamwidth as extending to just the half-powerpoints of the main lobe, each access node's antenna pattern may includeportions of RF radiation that extend outside of the desired area ofcoverage. FIGS. 2 and 3 illustrate examples of this, with exampleantenna patterns depicted on polar plots of power (e.g., decibels) anddirection (e.g., degrees) of radiation.

As shown in FIG. 2, portions of the antenna pattern's main lobe mayextend beyond the half-power points defining the desired beamwidth, sothat the main lobe includes both a desired portion and an undesiredportion. And as shown in FIG. 3, the antenna pattern may have one ormore minor lobes, including side lobes that radiate sideward and a backlobe that radiates in a direction 180 degrees opposite from the mainlobe, so that the main lobe includes an area of desired radiation andthe side lobes and back lobe define areas of undesired radiation. Otherexamples are possible as well.

As noted above, each access node's antenna structure could have arespective level of antenna pattern efficiency representing how well theantenna pattern of the antenna structure focuses energy in the desiredcoverage area rather than in an undesired area or direction. And asindicated above, example antenna-pattern-efficiency metrics couldinclude inverse SPR and FBR.

In an arrangement where an antenna structure is configured to provide anantenna pattern with a main lobe having a particular beamwidth in ahorizontal plane, for instance, antenna pattern efficiency of theantenna structure could be a ratio or percentage of how much energy theantenna pattern lobe radiates within that beamwidth versus how muchenergy the antenna structure spills over or radiates outside of thatbeamwidth, perhaps including side portions of the main lobe and one ormore side lobes, and perhaps not including a back lobe. The term “sectorpower ratio” (SPR) is generally used to describe the inverse, i.e., theratio of the power of the undesired radiation to the power of thedesired radiation of the main lobe, typically about 3 to 6%. So antennapattern efficiency (as opposed to inefficiency) could be characterizedas the inverse of the antenna structure's SPR (i.e., inverse SPR),perhaps on the order of about 94 to 97%.

Further, in the typical arrangement where an antenna pattern has a mainlobe (or front lobe) that defines the general direction and maximumradiated energy and also has a back lobe that extends in the oppositedirection, antenna pattern efficiency of the antenna structure could bea front to back ratio (FBR), i.e., a ratio of the power that the antennastructure radiates in the main lobe to the power that the antennastructure radiates in the back lobe.

The inverse SPR, FBR, and/or of one or more other such metricsrepresenting an access node's antenna pattern efficiency may depend onthe carrier frequency on which the access node provides the coverage andmay also depend on one or more other factors, such as configuration,age, and environmental conditions for instance. Further, these or othersuch metrics of an access node's antenna pattern efficiency could beestablished and recorded as attributes of the access node's coveragearea, individually and/or as a weighted combination. For instance, themetrics could be indicated by manufacture specifications and/or could becould be determined or updated from time to time based on measurementsof desired and undesired radiation from the antenna structure. And themetrics could be recorded at the access node and/or in a central datarepository or other node, possibly in correlation with an identifier ofthe coverage area.

In an example implementation, the core network 18 could be apacket-switched network, such as an Evolved Packet Core (EPC) network orNext Generation Core (NGC) network, supporting Internet Protocol (IP)communication and virtual packet tunnel interfaces between networknodes. In an example EPC arrangement as shown, for instance, the corenetwork 18 includes a serving gateway (SGW) 28, a packet data networkgateway (PGW) 30, a mobility management entity (MME) 32, a homesubscriber server (HSS) 34, and an element management system (EMS) 36,though other arrangements are possible as well.

With this arrangement, each access node could communicate with the SGW28, the SGW 28 could communicate with the PGW 30, and the PGW 30 couldprovide connectivity with a transport network 38, such as the Internet.Further, each access node could communicate with the MME 32, and the MME32 could communicate with the SGW 28, so that the MME 32 couldcoordinate setup of bearers for UEs to engage in packet-datacommunication. Alternatively, just one of the access nodes, such as the4G eNB 14, may so communicate with the MME 32.

Still further, the HSS 34 could include or otherwise have access to UEprofile records, which could specify service-subscription plans, UEconfigurations, and/or other such UE capability information. And the EMS36 could operate as the central repository noted above, storing variousoperational data and controlling and managing operation of variousnetwork elements.

FIG. 1 also depicts an example UE 40 that may be within coverage of cellsite 12 and may be served by the access nodes 14, 16. This UE could takeany of the forms noted above, among other possibilities and may have a4G LTE radio and associated RF circuitry and logic to support 4G LTEservice, a 5G NR radio and associated RF circuitry and logic to support5G NR service, and may further be configured to support EN-DC service.

In line with the discussion above, we can assume for present purposesthat UE 60 is currently served with EN-DC by the 4G eNB 14 and the 5GgNB 16, with a 4G connection on the carrier 20 on which the 4G eNB 14provides coverage and service, and a 5G connection one or the carrier 22on which the 5G gNB 14 provides coverage and service. For instance, theUE might have established a 4G connection with the 4G eNB 14 on carrier20, and the 4G eNB 14, operating as MN, might then have determined fromprofile data that the UE supports EN-DC service and might therefore havecoordinated setup of EN-DC service for the UE, including setup of a 5Gconnection with the 5G gNB 16 on carrier 22, and setup of a splitbearer.

With EN-DC service configured for the UE, the 4G eNB 14 and 5G gNB 16could then concurrently serve the UE, each over its respectiveconnection with the UE and each in the manner discussed above.

For instance, when the PGW 30 receives user-plane data from thetransport network 38 for transmission to the UE, that data may flow overa split access bearer, and the 4G eNB 14 may transmit a portion of thedata over the UE's 4G connection to the UE, while the 5G gNB 16 maytransmit another portion of the data over the UE's 5G connection to theUE. And when the UE has user-plane data to transmit on the transportnetwork 38, the UE may transmit a portion of the data over its 4Gconnection to the 4G eNB 14, which may forward the data over an accessbearer for transmission directly or indirectly through the core network18 to the transport network 38, and the UE may transmit another portionof the data over its 5G connection to the 5G gNB 16, which may likewiseforward the data over an access bearer for transmission directly orindirectly through the core network 18 to the transport network 38.

In line with the discussion above, in this EN-DC arrangement, the 4G eNB14, as MN, could be responsible for controlling the extent to which theUE provides uplink transmission on the UE's 4G connection versus on theUE's 5G connection. To exert this control, the 4G eNB 14 could engage inRRC signaling or the like with the UE, directing the UE how the UEshould distribute the UE's uplink communication, and the UE couldrespond to such directives from the 4G eNB 14 by handling the UE'suplink communications accordingly.

For example, the 4G eNB 14 may select either of the UE's 4G and 5Gconnections to be the UE's primary uplink path that the UE would useexclusively for the UE's uplink communication until the rate of the UE'suplink data flow exceeds a threshold level. The 4G eNB 14 may thereforetransmit to the UE an RRC message that specifies the selected connectionas the UE's primary uplink path. And in response, the UE may thusrestrict its uplink communications to that connection unless and untilthe UE transitions to the split-uplink mode. Thus, when the UE hasuplink data to transmit, the UE may transmit the data on just theselected, designated connection, to the access node serving thatconnection.

Further, the 4G eNB 14 may set an uplink data-rate threshold or othertrigger for transitioning the UE to the split-uplink mode. And the 4GeNB 14 might inform the UE of that trigger to enable the UE to do thetransitioning itself when the trigger occurs, or the 4G eNB 14 mightmonitor for occurrence of the trigger and, when the trigger occurs, thendirect the UE to transition the split-uplink mode.

Still further, when the UE is or will operate in the split-uplink mode,the 4G eNB 14 may decide what the UE's uplink split ratio should be,such as what percentage of the UE's uplink user-plane data flow the UEshould transmit over its 4G connection to the 4G eNB 14 versus whatpercentage of the UE's uplink user-plane data flow the UE shouldtransmit over its 5G connection to the 5G gNB 16. The 4G eNB 14 maytherefore transmit to the UE an RRC message that specifies the uplinksplit ratio. And in response, the UE may split its uplink datacommunications accordingly, transmitting the designated portion of itsdata on its 4G connection to the 4G eNB and transmitting the otherdesignated portion of its data on its 5G connection to the 5G gNB.

In line with the discussion above, the 4G eNB 14 could control varioussuch aspects of the UE's uplink communication based on a comparison ofthe levels of antenna pattern efficiency associated respectively witheach of the UE's connections. For instance, based on such a comparison,the 4G eNB 14 could select as the UE's primary uplink path the UE'sconnection having the higher associated antenna pattern efficiency.And/or based on such a comparison, the 4G eNB 14 could set an uplinksplit ratio for application by the UE. (At an extreme, an uplink splitratio of 100% on one connection and 0% on the other connection couldlikewise amount to setting as the UE's primary uplink path theconnection to which the UE will exclusively limit its uplink user-planecommunication.)

The level of antenna pattern efficiency associated respectively witheach of the UE's connections could be a level of antenna patternefficiency most recently established for the antenna structure thatprovides the coverage area in which that the air-interface connection isdefined. As discussed above, that level of antenna pattern efficiencycould be represented by various metrics, such as inverse SPR, FBR, orperhaps a weighted combination of these and/or other metrics.

And the 4G eNB 14 could learn the level of antenna pattern efficiencyassociated respectively with each of the UE's air-interface connectionsin various ways. As to the UE's connection with the 4G eNB 14, forinstance, the 4G eNB 14 could determine the associated level of antennapattern efficiency by referring to access node profile data stored atthe access node and/or by querying the EMS 36. And as to the UE'sconnection with the 5G gNB 16, the 4G eNB 14 could determine theassociated level of antenna pattern efficiency by querying the 5G gNB 16and/or the EMS 36.

The 4G eNB 14 could then use a comparison of these measures as a basisto control the UE's uplink communication as noted above.

For example, the 4G eNB 14 could determine that a given one of the UE'sconnections has a higher level of antenna pattern efficiency (e.g.,higher inverse SPR, lower SPR, and/or higher FBR) than the UE's otherconnection, and, based at least on this determination, the 4G eNB 14could select the given connection to be the UE's primary uplink path andcould configure the UE accordingly.

As another example, the 4G eNB 14 could control whether the UE operatesin single-connection-uplink mode or rather in split-uplink mode, basedon whether the levels of antenna pattern efficiency of the UE'sconnections are threshold different from each other. For instance, ifthe 4G eNB 14 determines that a difference between the levels of antennapattern efficiency of the UE's connections is at least as low as athreshold level, then, based at least on that determination, the 4G eNB14 could direct the UE to operate in the split-uplink mode rather thanin the single-connection-uplink mode. Whereas, if the 4G eNB 14determines that the difference between the levels of antenna patternefficiency of the UE's connections is greater than that or anotherhigher threshold level, then, based at least on that determination, the4G eNB 14 could direct the UE to operate in the single-connection-uplinkmode rather than in the split-uplink mode.

And as yet another example, when the UE is or will operate in thesplit-uplink mode, the 4G eNB 14 could establish and configure the UE toapply an uplink split ratio based on a comparison of the levels ofantenna pattern efficiency of the UE's connections. As noted above, forinstance, the 4G eNB 14 could set the uplink split ratio to provide amajority of the UE's uplink data flow on the air-interface connectionthat has the higher level of antenna pattern efficiency. For instance,if the 4G eNB 14 determines that the level of antenna pattern efficiencyof the UE's 4G connection is 94% and the level of antenna patternefficiency of the UE's 5G connection is 97%, then the 4G eNB 14 mayconfigure the UE's uplink split ratio to provide a majority of the UE'suplink data flow on the UE's 5G connection and the remainder on the UE's4G connection.

Variations from these examples, including consideration of additionalfactors as well, and controlling other aspects of the dual-connectedUE's uplink communication, could be possible too. FIG. 4 is next a flowchart depicting an example method that could be carried out inaccordance with the present disclosure to control uplink communicationfrom UE that has at least two co-existing air-interface connectionsincluding a first air-interface connection with a first access node anda second air-interface connection with a second access node. As shown inFIG. 2, at block 42, the example method includes comparing a level ofantenna pattern efficiency associated with the first air-interfaceconnection with a level of antenna pattern efficiency associated withthe second air-interface connection. And at block 44, the example methodincludes, based at least on the comparing, configuring an uplink splitratio defining a distribution of uplink user-plane data flow of the UEbetween at least the first air-interface connection and the secondair-interface connection.

In line with the discussion above, this method could be carried out by agiven one of the first and second access nodes. And in that case,configuring the uplink split ratio could involve transmitting from thegiven access node to the UE a directive (e.g., an RRCconnection-reconfiguration message) that causes the UE to implement theuplink split ratio.

Further, as discussed above, the first access node could have a firstantenna structure that radiates to define a first antenna patterndefining a first coverage area in which the first air-interfaceconnection is established, in which case the level of antenna patternefficiency associated with the first air-interface connection couldcomprise a level of antenna pattern efficiency of the first antennastructure. And likewise, the second access node could have a secondantenna structure that radiates to define a second antenna patterndefining a second coverage area in which the second air-interfaceconnection is established, in which case the level of antenna patternefficiency associated with the second air-interface connection couldcomprise a level of antenna pattern efficiency of the second antennastructure.

In addition, as discussed above, the level of antenna pattern efficiencyof the first antenna structure could be based on an SPR of the firstantenna pattern (e.g., an inverse SPR), and wherein the level of antennapattern efficiency of the second antenna structure could be based on anSPR of the second antenna pattern. And/or the level of antenna patternefficiency of the first antenna structure could be based on an FBR ofthe first antenna pattern, and the level of antenna pattern efficiencyof the second antenna structure could be based on an FBR of the secondantenna pattern.

As further discussed above, the UE could have a single-connection-uplinkmode of operation in which the uplink split ratio is 100% of the uplinkuser-plane data flow on just one of the first and second air-interfaceconnections and 0% of the uplink user-plane data flow on the other ofthe first and second air-interface connections.

And in that case, the act of configuring the uplink split ratio based atleast on the comparing could involve (i) based on the comparing,selecting a given one of the first and second air-interface connectionsto be the one air-interface connection on which the UE will provide 100%of the uplink user-plane data flow in the single-connection-uplink modeand (ii) configuring the UE in accordance with the selecting. Here, forinstance, the selecting of the given air-interface connection based onthe comparing could involve selecting the given air-interface connectionbased on a determination that antenna pattern efficiency associated withthe given air-interface connection is higher than the antenna patternefficiency associated with the other of the first and secondair-interface connections.

Further, the UE could also have an uplink-split mode of operation inwhich the uplink data split is greater than 0% respectively on each ofthe air-interface connections, i.e., where the UE transmits some of itsuplink data flow on one of the air-interface connections and other ofits uplink data flow on the other of the air-interface connections. Andin that case, the act of configuring the uplink split ratio based on thecomparing could involve (i) based on the comparing, selecting betweenthe UE operating in the single-connection-uplink mode and the UEoperating in the split-uplink mode and (ii) configuring the UE inaccordance with the selecting.

Still further, the act of configuring the uplink split ratio based atleast on the comparing could involve (i) based on the comparing,selecting a given one of the first and second air-interface connectionsto carry a majority of the uplink user-plane data flow of the UE and(ii) configuring the UE in accordance with the selecting. Here, forinstance, the UE could be configured to transmit greater than 50% of itsuplink user-plane data flow on the selected air-interface connection andless than 50% of its uplink user-plane data flow on the other of thefirst and second air-interface connections. And the selecting of thegiven air-interface connection based on the comparing could involveselecting the given air-interface connection based on a determinationthat the antenna pattern efficiency associated with the givenair-interface connection is higher than the antenna pattern efficiencyassociated with the other of the first and second air-interfaceconnections.

FIG. 5 is next another flow chart of an example method that could becarried out in accordance with the present disclosure to control uplinkcommunication from a UE that has at least two co-existing air-interfaceconnections including a first air-interface connection with a firstaccess node and a second air-interface connection with a second accessnode. This method could be operable in a scenario where one of the firstand second air-interface connections would define a primary uplink pathof the UE to which the UE would restrict its uplink user-plane datatransmission unless and until a trigger condition causes the UE to splitits uplink user-plane data transmission between the first and secondair-interface connections.

As shown in FIG. 3, at block 46, the example method includes comparing alevel of antenna pattern efficiency associated with the firstair-interface connection with a level of antenna pattern efficiencyassociated with the second air-interface connection. Further, at block48, the example method includes selecting, based at least on thecomparing, one of the first and second air-interface connections to bethe primary uplink path of the UE. And at block 50, the example methodincludes configuring the UE in accordance with the selecting.

Various features described above can be implemented in this context aswell, and vice versa.

For instance, the act of selecting, based at least on the comparing, oneof the first and second air-interface connections to be the primaryuplink path of the UE could involve (i) determining, based on thecomparing, that the level of antenna pattern efficiency associated withthe first air-interface connection is greater than the level of antennapattern efficiency associated with the second air-interface connectionand (ii) based at least on the determining, selecting the firstair-interface connection to be the primary uplink path of the UE.

Finally, FIG. 6 is a simplified block diagram of an example first accessnode that could implement various features described herein, to controluplink communication from a UE that has at least two co-existingair-interface connections including a first air-interface connectionwith the first access node and a second air-interface connection with asecond access node. For instance, the first access node could be an MNserving the UE while the UE has dual-connectivity, such as a 4G eNB thatserves the UE as part of EN-DC.

As shown in FIG. 6, the example first access node includes a wirelesscommunication interface 52, a backhaul communication interface 54, and acontroller 56, all of which could be integrated together and/orcommunicatively linked together by a system bus, network, or otherconnection mechanism 58.

In an example implementation, the wireless communication interface 52could comprise an antenna structure, which could be tower mounted orcould take other forms, and associated components such as a poweramplifier and a wireless transceiver, so as to facilitate providingcoverage on one or more carriers and serving the UE over the firstair-interface connection. And the backhaul communication interface 54could comprise network communication interface such as an Ethernetinterface, through which the first access node engages in backhaulcommunication.

Further, the controller 56 could comprise one or more processing units(e.g., one or more general purpose processors and/or specializedprocessors) programmed to cause the first access node to carry outvarious operations such as those discussed above. For instance, thecontroller 56 could comprise one or more non-transitory data storageunits (e.g., one or more magnetic, optical, or flash storage components)which could store program instructions executable by the one or moreprocessing units to cause the first access node to carry out suchoperations.

Various other features discussed herein can be implemented in thiscontext as well, and vice versa.

The present disclosure also contemplates at least one non-transitorycomputer readable medium having stored thereon (e.g., being encodedwith) program instructions executable by at least one processing unit tocarry out various operations described above.

Exemplary embodiments have been described above. Those skilled in theart will understand, however, that changes and modifications may be madeto these embodiments without departing from the true scope and spirit ofthe invention.

What is claimed is:
 1. A method for controlling uplink communicationfrom a user equipment device (UE) that has at least two co-existingair-interface connections including a first air-interface connectionwith a first access node and a second air-interface connection with asecond access node, the method comprising: comparing a level of antennapattern efficiency associated with the first air-interface connectionwith a level of antenna pattern efficiency associated with the secondair-interface connection; and based at least on the comparing,configuring an uplink split ratio defining a distribution of uplinkuser-plane data flow of the UE between at least the first air-interfaceconnection and the second air-interface connection, wherein the firstaccess node has a first antenna structure that radiates to define afirst antenna pattern defining a first coverage area in which the firstair-interface connection is established, and wherein the level ofantenna pattern efficiency associated with the first air-interfaceconnection comprises a level of antenna pattern efficiency of the firstantenna structure based on at least one factor selected from the groupconsisting of (i) a sector power ratio of the first antenna pattern and(ii) a front to back ratio of the first antenna pattern, and wherein thesecond access node has a second antenna structure that radiates todefine a second antenna pattern defining a second coverage area in whichthe second air-interface connection is established, and wherein thelevel of antenna pattern efficiency associated with the secondair-interface connection comprises a level of antenna pattern efficiencyof the second antenna structure based on at least one factor selectedfrom the group consisting of (i) a sector power ratio of the secondantenna pattern and (ii) a front to back ratio of the second antennapattern.
 2. The method of claim 1, wherein the method is carried out bya given one of the first and second access nodes, and whereinconfiguring the uplink split ratio comprises transmitting from the givenaccess node to the UE a directive that causes the UE to implement theuplink split ratio.
 3. The method of claim 1, wherein the UE has asingle-connection-uplink mode of operation in which the uplink splitratio is 100% of the uplink user-plane data flow on just one of thefirst and second air-interface connections and 0% of the uplinkuser-plane data flow on the other of the first and second air-interfaceconnections, and wherein configuring the uplink split ratio based atleast on the comparing comprises (i) based on the comparing, selecting agiven one of the first and second air-interface connections to be theone air-interface connection on which the UE will provide 100% of theuplink user-plane data flow in the single-connection-uplink mode ofoperation and (ii) configuring the UE in accordance with the selecting.4. The method of claim 3, wherein selecting the given air-interfaceconnection based on the comparing comprises selecting the givenair-interface connection based on a determination that the antennapattern efficiency associated with the given air-interface connection ishigher than the antenna pattern efficiency associated with the other ofthe first and second air-interface connections.
 5. The method of claim1, wherein the UE has a single-connection-uplink mode of operation inwhich the uplink data split is 100% on one air-interface connection and0% on the other air-interface connection, and the UE has an uplink-splitmode of operation in which the uplink data split is greater than 0%respectively on each of the air-interface connections, and whereinconfiguring the uplink split ratio based on the comparing comprises (i)based on the comparing, selecting between the UE operating in thesingle-connection-uplink mode and the UE operating in the split-uplinkmode and (ii) configuring the UE in accordance with the selecting. 6.The method of claim 1, wherein configuring the uplink split ratio basedat least on the comparing comprises (i) based on the comparing,selecting a given one of the first and second air-interface connectionsto carry a majority of the uplink user-plane data flow of the UE and(ii) configuring the UE in accordance with the selecting.
 7. The methodof claim 6, wherein selecting the given air-interface connection basedon the comparing comprises selecting the given air-interface connectionbased on a determination that the antenna pattern efficiency associatedwith the given air-interface connection is higher than the antennapattern efficiency associated with the other of the first and secondair-interface connections.
 8. A first access node operable to controluplink communication from a user equipment device (UE) that has at leasttwo co-existing air-interface connections including a firstair-interface connection with the first access node and a secondair-interface connection with a second access node, the first accessnode comprising: a wireless communication interface including an antennastructure through which to serve the UE over the first air-interfaceconnection; a backhaul communication interface through which the engagein backhaul communication; and a controller, wherein the controllercauses the first access node to carry out operations including:comparing a level of antenna pattern efficiency associated with thefirst air-interface connection with a level of antenna patternefficiency associated with the second air-interface connection, andbased at least on the comparing, configuring an uplink split ratiodefining a distribution of uplink user-plane data flow of the UE betweenat least the first air-interface connection and the second air-interfaceconnection, wherein the first access node has a first antenna structurethat radiates to define a first antenna pattern defining a firstcoverage area in which the first air-interface connection isestablished, and wherein the level of antenna pattern efficiencyassociated with the first air-interface connection comprises a level ofantenna pattern efficiency of the first antenna structure based on atleast one factor selected from the group consisting of (i) a sectorpower ratio of the first antenna pattern and (ii) a front to back ratioof the first antenna pattern, and wherein the second access node has asecond antenna structure that radiates to define a second antennapattern defining a second coverage area in which the secondair-interface connection is established, and wherein the level ofantenna pattern efficiency associated with the second air-interfaceconnection comprises a level of antenna pattern efficiency of the secondantenna structure based on at least one factor selected from the groupconsisting of (i) a sector power ratio of the second antenna pattern and(ii) a front to back ratio of the second antenna pattern.
 9. The firstaccess node of claim 8, wherein the controller comprises a processingunit, non-transitory data storage, and program instructions stored inthe non-transitory data storage and executable by the processing unit tocarry out the operations.
 10. The first access node of claim 8, whereinthe UE has a single-connection-uplink mode in which the uplink splitratio is 100% of the uplink user-plane data flow on just one of thefirst and second air-interface connections and 0% of the uplinkuser-plane data flow on the other of the first and second air-interfaceconnections, and wherein configuring the uplink split ratio based atleast on the comparing comprises (i) based on the comparing, determiningthat the antenna pattern efficiency associated with the firstair-interface connection is higher than the antenna pattern efficiencyassociated with the second air-interface connection, (ii) based at leaston the determining, selecting a given one of the first and secondair-interface connections to be the one air-interface connection onwhich the UE will provide 100% of the uplink user-plane data flow in thesingle-connection-uplink mode and (iii) configuring the UE in accordancewith the selecting.
 11. The first access node of claim 8, whereinconfiguring the uplink split ratio based at least on the comparingcomprises (i) based on the comparing, determining that the antennapattern efficiency associated with the first air-interface connection ishigher than the antenna pattern efficiency associated with the secondair-interface connection, (ii) based at least on the determining,selecting the first air-interface connection to carry a majority of theuplink user-plane data flow of the UE and (iii) configuring the UE inaccordance with the selecting.
 12. A method for controlling uplinkcommunication from a user equipment device (UE) that has at least twoco-existing air-interface connections including a first air-interfaceconnection with a first access node and a second air-interfaceconnection with a second access node, the method comprising: comparing alevel of antenna pattern efficiency associated with the firstair-interface connection with a level of antenna pattern efficiencyassociated with the second air-interface connection; and based at leaston the comparing, configuring an uplink split ratio defining adistribution of uplink user-plane data flow of the UE between at leastthe first air-interface connection and the second air-interfaceconnection, wherein configuring the uplink split ratio based at least onthe comparing comprises (i) based on the comparing, selecting a givenone of the first and second air-interface connections to carry amajority of the uplink user-plane data flow of the UE and (ii)configuring the UE in accordance with the selecting, and whereinselecting the given air-interface connection based on the comparingcomprises selecting the given air-interface connection based on adetermination that the antenna pattern efficiency associated with thegiven air-interface connection is higher than the antenna patternefficiency associated with the other of the first and secondair-interface connections.
 13. The method of claim 12, wherein themethod is carried out by a given one of the first and second accessnodes, and wherein configuring the uplink split ratio comprisestransmitting from the given access node to the UE a directive thatcauses the UE to implement the uplink split ratio.
 14. The method ofclaim 12, wherein the UE has a single-connection-uplink mode ofoperation in which the uplink split ratio is 100% of the uplinkuser-plane data flow on just one of the first and second air-interfaceconnections and 0% of the uplink user-plane data flow on the other ofthe first and second air-interface connections, and wherein configuringthe uplink split ratio based at least on the comparing comprises (i)based on the comparing, selecting a given one of the first and secondair-interface connections to be the one air-interface connection onwhich the UE will provide 100% of the uplink user-plane data flow in thesingle-connection-uplink mode of operation and (ii) configuring the UEin accordance with the selecting.
 15. The method of claim 14, whereinselecting the given air-interface connection based on the comparingcomprises selecting the given air-interface connection based on adetermination that the antenna pattern efficiency associated with thegiven air-interface connection is higher than the antenna patternefficiency associated with the other of the first and secondair-interface connections.
 16. The method of claim 12, wherein the UEhas a single-connection-uplink mode of operation in which the uplinkdata split is 100% on one air-interface connection and 0% on the otherair-interface connection, and the UE has an uplink-split mode ofoperation in which the uplink data split is greater than 0% respectivelyon each of the air-interface connections, and wherein configuring theuplink split ratio based on the comparing comprises (i) based on thecomparing, selecting between the UE operating in thesingle-connection-uplink mode and the UE operating in the split-uplinkmode and (ii) configuring the UE in accordance with the selecting. 17.The method of claim 12, wherein the first access node has a firstantenna structure that radiates to define a first antenna patterndefining a first coverage area in which the first air-interfaceconnection is established, and wherein the level of antenna patternefficiency associated with the first air-interface connection is basedon a sector power ratio of the first antenna pattern, and wherein thesecond access node has a second antenna structure that radiates todefine a second antenna pattern defining a second coverage area in whichthe second air-interface connection is established, and wherein thelevel of antenna pattern efficiency associated with the secondair-interface connection is based on a sector power ratio of the secondantenna pattern.
 18. The method of claim 12, wherein the first accessnode has a first antenna structure that radiates to define a firstantenna pattern defining a first coverage area in which the firstair-interface connection is established, and wherein the level ofantenna pattern efficiency associated with the first air-interfaceconnection is based on a front to back ratio of the first antennapattern, and wherein the second access node has a second antennastructure that radiates to define a second antenna pattern defining asecond coverage area in which the second air-interface connection isestablished, and wherein the level of antenna pattern efficiencyassociated with the second air-interface connection is based on a frontto back ratio of the second antenna pattern.